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Publication numberUS8068201 B2
Publication typeGrant
Application numberUS 12/519,447
Publication dateNov 29, 2011
Filing dateNov 30, 2007
Priority dateDec 18, 2006
Also published asCN101568877A, CN101568877B, US20100060813, WO2008075549A1
Publication number12519447, 519447, US 8068201 B2, US 8068201B2, US-B2-8068201, US8068201 B2, US8068201B2
InventorsYuki Kawashima, Yasutoshi Tasaka
Original AssigneeSharp Kabushiki Kaisha
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Liquid crystal display having particular auxiliary electrode
US 8068201 B2
Abstract
A vertical orientation liquid crystal display in which orientation control by oblique electric field is performed stably and lowering in light transmission rate of the liquid crystal display is suppressed without increasing the number of manufacturing steps significantly. In the vertical orientation liquid crystal display, a plurality of regions having different inclination orientations of liquid crystal molecule are formed by applying a voltage to each pixel electrode having an aperture or a recessed portion. The liquid crystal display comprises a switching element connected electrically with the pixel electrode, and an auxiliary electrode formed to overlap the aperture or the recessed portion in the pixel electrode wherein the auxiliary electrode is formed of the same film as that of the semiconductor layer in the switching element.
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Claims(12)
1. A liquid crystal display device comprising a first substrate, a second substrate provided so as to oppose the first substrate, and a vertical-alignment type liquid crystal layer provided between the first substrate and the second substrate,
the liquid crystal display device having a plurality of pixels each including: a switching element which is provided on the first substrate and at least includes a semiconductor layer; a pixel electrode electrically connected to the switching element; a counter electrode opposing the pixel electrode; and the liquid crystal layer interposed between the pixel electrode and the counter electrode,
the pixel electrode including at least one aperture or recessed portion formed at a predetermined position in the pixel, and
in each of the pixels, when at least a predetermined voltage is applied across the liquid crystal layer, a plurality of regions being created where liquid crystal molecules tilt in respectively different azimuthal directions, wherein,
the first substrate includes an auxiliary electrode to which a different potential from that for the pixel electrode is applied; and
the auxiliary electrode includes a portion overlapping at least one aperture or recessed portion of the pixel electrode, and is made of a same film as the semiconductor layer of the switching element.
2. The liquid crystal display device of claim 1, wherein the auxiliary electrode further includes a portion located near an outer periphery of the pixel electrode.
3. The liquid crystal display device of claim 1, wherein, in each of the plurality of pixels, a plurality of liquid crystal domains each exhibiting an axisymmetric orientation are created when at least a predetermined voltage is applied across the liquid crystal layer.
4. The liquid crystal display device of claim 1, wherein a potential which is substantially the same as that for the counter electrode is applied to the auxiliary electrode.
5. The liquid crystal display device of claim 1, wherein the switching element is a thin film transistor whose channel region is a portion of the semiconductor layer.
6. The liquid crystal display device of claim 1, wherein the semiconductor layer and the auxiliary electrode are made of amorphous silicon or crystalline silicon.
7. The liquid crystal display device of claim 1, wherein the auxiliary electrode has a light transmittance of 60% or more.
8. The liquid crystal display device of claim 1, wherein,
the first substrate includes a storage capacitor line; and
the auxiliary electrode is electrically connected to the storage capacitor line.
9. The liquid crystal display device of claim 8, wherein,
the first substrate includes a connection electrode for electrically connecting the auxiliary electrode and the storage capacitor line; and
the connection electrode is provided outside a displaying region which is defined by the plurality of pixels.
10. The liquid crystal display device of claim 9, wherein,
the first substrate includes a signal line; and
the connection electrode is made of a same film as the signal line.
11. The liquid crystal display device of claim 8, wherein,
the first substrate includes a connection electrode for electrically connecting the auxiliary electrode and the storage capacitor line;
the connection electrode is provided in each of the plurality of pixels; and
the auxiliary electrode partially overlaps the storage capacitor line.
12. The liquid crystal display device of claim 11, wherein the connection electrode is disposed so that the entire connection electrode overlaps the storage capacitor line.
Description

This application is the U.S. national phase of International Application No. PCT/JP2007/073231 filed 30 Nov. 2007, which designated the U.S. and claims priority to Japan Application No. 2006-339795 filed 18 Dec. 2006, the entire contents of each of which are hereby incorporated by reference.

TECHNICAL FIELD

The present invention relates to a liquid crystal display device, and in particular to a liquid crystal display device which is suitably used in mobile information terminals (e.g., PDAs), mobile phones, liquid crystal displays for vehicle mounting, digital cameras, personal computers, amusement devices, television sets, and the like.

BACKGROUND ART

In recent years, on the strength of being thin and having a low power consumption, liquid crystal display devices are broadly used in laptop-type personal computers, mobile phones, information devices such as electronic organizers, camera-integrated VTRs having a liquid crystal monitor, and the like.

As a display mode which can realize a high contrast and a wide viewing angle, a vertical alignment mode utilizing a vertical-alignment type liquid crystal layer is drawing attention. In general, a vertical-alignment type liquid crystal layer is formed by using a liquid crystal material having negative dielectric anisotropy and vertical alignment films.

For example, Patent Document 1 discloses a liquid crystal display device whose viewing angle characteristics are improved by allowing an oblique electric field to be generated near an aperture that is provided in a counter electrode, and around a liquid crystal molecule within the aperture which is in a vertical alignment state, allowing the surrounding liquid crystal molecules to take an inclined orientation.

However, with the construction described in Patent Document 1, it is difficult to form an oblique electric field across the entire region within the pixel. This leads to a problem in that regions in which the liquid crystal molecules have a slow response to voltage occur within the pixel, thus causing an afterimage phenomenon.

In order to solve this problem, Patent Document 2 discloses a technique in which, regularly-arranged apertures are provided in the pixel electrode or the counter electrode to form a plurality of liquid crystal domains exhibiting axisymmetric orientation within the pixel.

Furthermore, Patent Document 3 discloses a technique of providing an auxiliary electrode for stably performing orientation control with an oblique electric field on an active matrix substrate. This auxiliary electrode is provided in a position corresponding to a slit which is formed in a pixel electrode. Moreover, this auxiliary electrode is formed integrally with a storage capacitor electrode for constituting a storage capacitor, and is formed concurrently with and from the same metal film as the gate lines, in a step of forming the gate lines.

  • [Patent Document 1] Japanese Laid-Open Patent Publication No. 6-301036
  • [Patent Document 2] Japanese Laid-Open Patent Publication No. 2000-47217
  • [Patent Document 3] Japanese Laid-Open Patent Publication No. 2006-184334
DISCLOSURE OF INVENTION Problems to be Solved by the Invention

However, since the auxiliary electrode disclosed in Patent Document 3 is made of a metal film, it lowers the aperture ratio of the pixel and decreases light transmittance. In order to solve this problem, it may be possible to compose the auxiliary electrode from a transparent ITO film. In this case, however, extra steps such as deposition and patterning of an ITO film (which needs to be separately formed in addition to the ITO film for composing the pixel electrode) must be provided, thus resulting in an increased number of steps.

The present invention has been made in view of the above problems, and an objective thereof is to stably perform orientation control with an oblique electric field in a liquid crystal display device of the vertical alignment mode, and suppress decrease in light transmittance without much increase in the number of production steps.

Means for Solving the Problems

A liquid crystal display device according to the present invention is a liquid crystal display device comprising a first substrate, a second substrate provided so as to oppose the first substrate, and a vertical-alignment type liquid crystal layer provided between the first substrate and the second substrate, the liquid crystal display device having a plurality of pixels each including: a switching element which is provided on the first substrate and at least includes a semiconductor layer; a pixel electrode electrically connected to the switching element; a counter electrode opposing the pixel electrode; and the liquid crystal layer interposed between the pixel electrode and the counter electrode, the pixel electrode including at least one aperture or recessed portion formed at a predetermined position in the pixel, and in each of the pixels, when at least a predetermined voltage is applied across the liquid crystal layer, a plurality of regions being created where liquid crystal molecules tilt in respectively different azimuthal directions, wherein, the first substrate includes an auxiliary electrode to which a different potential from that for the pixel electrode is applied; and the auxiliary electrode includes a portion overlapping at least one aperture or recessed portion of the pixel electrode, and is made of a same film as the semiconductor layer of the switching element.

In a preferred embodiment, the auxiliary electrode further includes a portion located near an outer periphery of the pixel electrode.

In a preferred embodiment, in each of the plurality of pixels, a plurality of liquid crystal domains each exhibiting an axisymmetric orientation are created when at least a predetermined voltage is applied across the liquid crystal layer.

In a preferred embodiment, a potential which is substantially the same as that for the counter electrode is applied to the auxiliary electrode.

In a preferred embodiment, the switching element is a thin film transistor whose channel region is a portion of the semiconductor layer.

In a preferred embodiment, the semiconductor layer and the auxiliary electrode are made of amorphous silicon or crystalline silicon.

In a preferred embodiment, the auxiliary electrode has a light transmittance of 60% or more.

In a preferred embodiment, the first substrate includes a storage capacitor line; and the auxiliary electrode is electrically connected to the storage capacitor line.

In a preferred embodiment, the first substrate includes a connection electrode for electrically connecting the auxiliary electrode and the storage capacitor line; and the connection electrode is provided outside a displaying region which is defined by the plurality of pixels.

In a preferred embodiment, the first substrate includes a connection electrode for electrically connecting the auxiliary electrode and the storage capacitor line; the connection electrode is provided in each of the plurality of pixels; and the auxiliary electrode partially overlaps the storage capacitor line.

In a preferred embodiment, the connection electrode is disposed so that the entire connection electrode overlaps the storage capacitor line.

In a preferred embodiment, the first substrate includes a signal line; and the connection electrode is made of a same film as the signal line.

Effects of the Invention

A liquid crystal display device according to the present invention has an auxiliary electrode which includes a portion overlapping an aperture or recessed portion of a pixel electrode. By applying a different potential from that for the pixel electrode to the auxiliary electrode, the intensity of an orientation restriction force due to an oblique electric field which is generated in the aperture or recessed portion can be controlled. For example, an oblique electric field whose equipotential lines dip more steeply in the aperture or recessed portion can be generated, whereby a strong orientation restriction force can be obtained. As a result, it is possible to stably perform orientation control with an oblique electric field. Since the auxiliary electrode is made of the same film as the semiconductor layer of the switching element, it is possible to suppress decrease in light transmittance without much increase in the number of production steps.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 An upper plan view schematically showing a liquid crystal display device 100 according to a preferred embodiment of the present invention.

FIG. 2 A cross-sectional view schematically showing a liquid crystal display device 100 according to a preferred embodiment of the present invention, showing a cross section along line 2A-2A′ in FIG. 1.

FIG. 3 A cross-sectional view schematically showing the liquid crystal display device 100 according to a preferred embodiment of the present invention, showing a cross section along line 3A-3A′ in FIG. 1.

FIG. 4 (a) to (c) are diagrams schematically showing orientations of liquid crystal molecules, where: (a) shows an orientation in the absence of an applied voltage; (b) shows an orientation immediately after voltage application; and (c) shows an orientation when a sufficient time has elapsed since voltage application.

FIG. 5 A diagram showing, by using equipotential lines, an electric field which is created when a voltage is applied across a liquid crystal layer, illustrating a case where no auxiliary electrode is provided.

FIG. 6 A diagram showing, by using equipotential lines, an electric field which is created when a voltage is applied across a liquid crystal layer, illustrating a case where substantially the same potential as that for a counter electrode is applied to an auxiliary electrode.

FIG. 7 A cross-sectional view schematically showing a liquid crystal display device 100′ according to a preferred embodiment of the present invention.

FIG. 8 A cross-sectional view schematically showing the liquid crystal display device 100′ according to a preferred embodiment of the present invention.

FIG. 9 An upper plan view schematically showing a liquid crystal display device 100 according to a preferred embodiment of the present invention.

FIG. 10 An upper plan view schematically showing a liquid crystal display device 200 according to a preferred embodiment of the present invention.

FIG. 11 A cross-sectional view schematically showing the liquid crystal display device 200 according to a preferred embodiment of the present invention, showing a cross section along line 11A-11A′ in FIG. 10.

FIG. 12 A cross-sectional view schematically showing the liquid crystal display device 200 according to a preferred embodiment of the present invention, showing a cross section along line 12A-12A′ in FIG. 10.

FIG. 13 A diagram showing a manner of electrical connection between auxiliary electrodes and storage capacitor lines in the liquid crystal display device 200.

FIG. 14 (a) to (c) are step-by-step cross-sectional views schematically showing steps of forming a connection electrode in the liquid crystal display device 200.

FIG. 15 A cross-sectional view schematically showing a liquid crystal display device 200′ according to a preferred embodiment of the present invention.

FIG. 16 A cross-sectional view schematically showing the liquid crystal display device 200′ according to a preferred embodiment of the present invention.

FIGS. 17 (a) and (b) are cross-sectional views showing exemplary constructions for establishing electrical connection between an auxiliary electrode and a storage capacitor line within a pixel.

FIG. 18 (a) is an upper plan view showing an exemplary construction for establishing electrical connection between an auxiliary electrode and a storage capacitor line within a pixel; and (b) is a cross-sectional view taken along line 18B-18B′ in (a).

FIG. 19 (a) is an upper plan view showing an exemplary construction for establishing electrical connection between an auxiliary electrode and a storage capacitor line within a pixel; and (b) is a cross-sectional view taken along line 19B-19B′ in (a).

FIG. 20 (a) is an upper plan view showing an exemplary construction for establishing electrical connection between an auxiliary electrode and a storage capacitor line within a pixel; and (b) is a cross-sectional view taken along line 20B-20B′ in (a).

FIG. 21 An upper plan view schematically showing a liquid crystal display device 300 according to a preferred embodiment of the present invention.

FIG. 22 A cross-sectional view schematically showing the liquid crystal display device 300 according to a preferred embodiment of the present invention, showing a cross section along line 22A-22A′ in FIG. 21.

FIG. 23 An upper plan view schematically showing a liquid crystal display device 400 according to a preferred embodiment of the present invention.

FIG. 24 A cross-sectional view schematically showing the liquid crystal display device 400 according to a preferred embodiment of the present invention, showing a cross section along line 24A-24A′ in FIG. 23.

DESCRIPTION OF REFERENCE NUMERALS

    • 1, 1′ thin film transistor (switching element)
    • 2 pixel electrode
    • 2 a recessed portion
    • 2T transparent electrode
    • 2R reflection electrode
    • 3 counter electrode
    • 4 auxiliary electrode
    • 4 a portion of auxiliary electrode (portion overlapping recessed portion of pixel electrode)
    • 4 b portion of auxiliary electrode (portion located near outer periphery of pixel electrode)
    • 4 c portion of auxiliary electrode (portion overlapping electrically-conductive film of pixel electrode)
    • 4 d portion of auxiliary electrode (portion connected to auxiliary electrode of adjoining pixel)
    • 5 connection electrode
    • 6 protrusion
    • 10, 30 transparent substrate
    • 11 basecoat film
    • 12 semiconductor layer
    • 13 gate insulating film
    • 14 gate electrode
    • 15 scanning line
    • 16 storage capacitor line
    • 17 first interlayer insulating film
    • 18 source electrode
    • 19 drain electrode
    • 20 signal line
    • 21 second interlayer insulating film
    • 22, 33 vertical alignment film
    • 23, 34 polarizer
    • 31 color filter
    • 32 light shielding layer (black matrix)
    • 50 liquid crystal layer
    • 51 liquid crystal molecules
    • 60 active matrix substrate
    • 70 counter substrate (color filter substrate)
    • 100, 100′, 200, 200′ liquid crystal display device
    • 300, 400 liquid crystal display device
BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, with reference to the drawings, embodiments of the present invention will be described. Note that the present invention is not limited to the following embodiments.

Embodiment 1

With reference to FIG. 1 to FIG. 3, the structure of a liquid crystal display device 100 according to the present embodiment will be described. FIG. 1 is an upper plan view schematically showing a region corresponding to one pixel of the liquid crystal display device 100. FIG. 2 and FIG. 3 are cross-sectional views along lines 2A-2A′ and 3A-3A′ in FIG. 1, respectively.

The liquid crystal display device 100 includes an active matrix substrate 60, a counter substrate (color filter substrate) 70 provided so as to oppose the active matrix substrate 60, and a vertical-alignment type liquid crystal layer 50 provided therebetween.

Each of the plurality of pixels of the liquid crystal display device 100 includes a thin film transistor (TFT) 1 provided on the active matrix substrate 60, a pixel electrode 2 electrically connected to the thin film transistor 1, a counter electrode 3 opposing the pixel electrode 2, and a liquid crystal layer 50 interposed between the pixel electrode 2 and the counter electrode 3.

Hereinafter, the more specific structure of the active matrix substrate 60 and the counter substrate 70 will be described.

The active matrix substrate 60 includes a transparent substrate (e.g., a glass substrate or a plastic substrate) 10 supporting its component elements. A basecoat film 11 is formed on a surface of the transparent substrate 10 closer to the liquid crystal layer 50, and a semiconductor layer 12 of continuous grain silicon (CGS) is formed on the basecoat film 11. A portion of the semiconductor layer 12 functions as a channel region of the thin film transistor 1, and other portions function as a source region and a drain region.

A gate insulating film 13 is formed so as to cover the semiconductor layer 12. A gate electrode 14, a scanning line 15, and a storage capacitor line 16 are formed on the gate insulating film 13, and a first interlayer insulating film 17 is formed so as to cover them.

On the first interlayer insulating film 17, a source electrode 18, a drain electrode 19, and a signal line 20 are formed. In contact holes which are formed in the gate insulating film 13 and the first interlayer insulating film 17, the source electrode 18 and the drain electrode 19 are connected to the semiconductor layer 12.

A second interlayer insulating film 21 is formed so as to cover the source electrode 18, the drain electrode 19, and the signal line 20, and a pixel electrode 2 is provided on the second interlayer insulating film 21. The second interlayer insulating film 21 is an organic insulating film made of an acrylic type photosensitive resin or the like, for example. The pixel electrode 2 is made of a transparent electrically conductive material (e.g. ITO). On a surface of the transparent substrate 10 opposite from the liquid crystal layer 50, a polarizer 23 is provided.

On a surface of the transparent substrate 30 closer to the liquid crystal layer 50, the counter substrate 70 includes a color filter 31, a light shielding layer (also referred to as a black matrix) 32, and the counter electrode in this order. The counter electrode 3 is made of a transparent electrically conductive material (e.g. ITO). On a surface of the transparent substrate 30 opposite from the liquid crystal layer 50, a polarizer 34 is provided.

The liquid crystal layer 50 interposed between the active matrix substrate 60 and the counter substrate 70 is made of a nematic liquid crystal material having a negative dielectric anisotropy, and contains a chiral agent as necessary. On surfaces of the active matrix substrate 60 and the counter substrate 70 that are in contact with the liquid crystal layer 50, vertical alignment films 22 and 33 are provided. The vertical alignment films 22 and 33 cause liquid crystal molecules 51 in the liquid crystal layer 50 to be aligned substantially perpendicular to their surfaces. The vertical alignment films 22 and 33 are made of polyimide resin, for example.

A pixel electrode 2 of the liquid crystal display device 100 includes a plurality of recessed portions 2 a formed at predetermined positions in the pixel. In the present embodiment, four recessed portions 2 a are provided in the pixel electrode 2, and the pixel is divided into three regions by the recessed portions 2 a. The individual regions divided by the recessed portions 2 a are also referred to as subpixels.

When a predetermined potential difference is given between the pixel electrode 2 and the counter electrode 3 (i.e., a predetermined voltage is applied across the liquid crystal layer 50), an oblique electric field (a potential gradient which is tilted with respect to the substrate surface) is generated near the outer periphery of the pixel electrode 2 and at the recessed portions 2 a, and this oblique electric field defines the directions in which the liquid crystal molecules 51 fall. Due to the action of the oblique electric field, a plurality of (herein three) liquid crystal domains are created each exhibiting an axisymmetric orientation. In each liquid crystal domain, the liquid crystal molecules 51 are orientated in almost all azimuthal directions, and thus, when a voltage is applied across the liquid crystal layer 50, a plurality of regions are formed in which the liquid crystal molecules 51 are tilted in respectively different azimuthal directions in the liquid crystal display device 100.

With reference to FIG. 4, the mechanism by which axisymmetric orientations are created will be described more specifically. FIGS. 4( a) to (c) are diagrams schematically showing orientations of the liquid crystal molecules 51, where: FIG. 4( a) shows a state in the absence of an applied voltage; FIG. 4( b) shows a state immediately after voltage application; and FIG. 4( c) shows a state when a sufficient time has elapsed since voltage application.

As shown in FIG. 4( a), in the absence of an applied voltage, the liquid crystal molecules 51 are orientated substantially perpendicularly to the substrate surface due to the orientation restriction forces of the vertical alignment films 22 and 33.

Under an applied voltage, the liquid crystal molecules 51 having a negative dielectric anisotropy are tilted so that their molecular major axes are perpendicular to the electric lines of force (i.e., parallel to the equipotential lines), and therefore, the directions in which the liquid crystal molecules 51 fall are defined by an oblique electric field which is generated near the outer periphery of and at the recessed portions 2 a of the pixel electrode 2. Therefore, as shown in FIG. 4( b), the liquid crystal molecules 51 in the region where the oblique electric field is generated (i.e., the liquid crystal molecules 51 which directly receive the orientation restriction force due to the oblique electric field) are the first to be tilted.

Thereafter, with lapse of time, the other liquid crystal molecules 51 will be orientated in continuous manners (so as to match the orientations of the liquid crystal molecules 51 that were the first to be tilted), whereby liquid crystal domains as shown in FIG. 4( c) are formed. Since the liquid crystal molecules 51 are orientated in almost all azimuthal directions (all azimuthal directions within the substrate plane) in each liquid crystal domain, the liquid crystal display device 100 has excellent viewing angle characteristics.

Herein, “axisymmetric orientation” is synonymous with “radially-inclined orientation” in Patent Document 1. Around the center axis of axisymmetric orientation, the liquid crystal molecules 51 are continuously oriented without forming disclination lines, and the major axes of the liquid crystal molecules 51 are oriented in a radial, tangential, or spiral manner. In either case, the major axes of the liquid crystal molecules 51 have components which are radially-inclined from the center of orientation (components which are parallel to the oblique electric field).

Note that it is not necessary that a plurality of recessed portions 2 a be provided as is exemplified herein; it suffices if at least one recessed portion 2 a is provided. For example, in the case where a pixel is divided into two regions, liquid crystal domains with axisymmetric orientations can be created by providing only one oblong recessed portion 2 a. Moreover, an aperture may be provided instead of a recessed portion 2 a (or in addition to a recessed portion 2 a). In the case where an aperture is provided in the pixel electrode 2, as in the case of a recessed portion 2 a, an oblique electric field is formed in any aperture surrounded by the electrically-conductive film of the pixel electrode 2, thus defining the directions in which the liquid crystal molecules 51 are tilted due to an electric field.

Next, the construction of the liquid crystal display device 100 according to the present embodiment will be described in more detail.

As shown in FIG. 1 to FIG. 3, the active matrix substrate 60 of the liquid crystal display device 100 includes auxiliary electrodes 4 to which a different potential from that for the pixel electrode 2 is applied. As shown in FIG. 3, an auxiliary electrode 4 in the present embodiment is connected to the storage capacitor line 16 through a contact hole which is formed in the gate insulating film 13, whereby a potential (e.g., the same potential as that for the counter electrode 3 as will be described later) which is different from that for the pixel electrode 2 can be applied to the auxiliary electrode 4.

As shown in FIG. 1, an auxiliary electrode 4 includes portions 4 a which overlap the recessed portions 2 a of the pixel electrode 2, and a portion 4 b which is located near the outer periphery of the pixel electrode 2. Moreover, the auxiliary electrode 4 is made of the same film as the semiconductor layer 12 of the thin film transistor 1. In other words, the auxiliary electrode 4 is formed concurrently with the semiconductor layer 12 by patterning the semiconductor film for forming the semiconductor layer 12 of the thin film transistor 1.

The liquid crystal display device 100 of the present embodiment includes auxiliary electrodes 4 as described above. By applying a different potential from that for the pixel electrode 2 to each auxiliary electrode 4, it becomes possible to control the intensity of the orientation restriction force due to an oblique electric field. Hereinafter, this point will be described in more detail.

FIG. 5 and FIG. 6 are diagrams showing, by using equipotential lines EQ, electric fields which are created when a voltage is applied across the liquid crystal layer 50. FIG. 5 illustrates a case where auxiliary electrodes 4 are not provided, whereas FIG. 6 illustrates a case where substantially the same potential as that for the counter electrode 3 is applied to an auxiliary electrode 4.

When a voltage is applied across the liquid crystal layer 50, as shown in FIG. 5 and FIG. 6, a potential gradient which is represented by equipotential lines (which are orthogonal to electric lines of force) EQ is created. The equipotential lines EQ run parallel to the substrate surface in the liquid crystal layer 50 which is interposed between the electrically-conductive film of the pixel electrode 2 (i.e., the portion excluding the recessed portions 2 a) and the counter electrode 3, and dip in any region corresponding to the neighborhood of the outer periphery of and the recessed portions 2 a of the pixel electrode 2. Therefore, in the liquid crystal layer 50 in any region corresponding to the neighborhood of the outer periphery of and the recessed portions 2 a of the pixel electrode 2, an oblique electric field which is represented by tilted equipotential lines EQ is created.

In the case where auxiliary electrodes 4 are not provided, as shown in FIG. 5, equipotential lines EQ are continuous between adjoining subpixels, so that the equipotential lines EQ present continuous rises and falls. In other words, a relatively gentle potential gradient is created.

On the other hand, in the case where an auxiliary electrode 4 is provided and substantially the same potential as that for the counter electrode 3 is applied to the auxiliary electrode 4, as shown in FIG. 6, equipotential lines EQ are not continuous between adjoining subpixels, but the equipotential lines EQ abruptly dip above the recessed portion 2 a. Therefore, a steep potential gradient is created in the recessed portion 2 a, thus resulting in a stronger oblique electric field than that shown in FIG. 5. Therefore, a strong orientation restriction force can be obtained.

As described above, since the liquid crystal display device 100 in the present embodiment includes the auxiliary electrodes 4, orientation control can be stably performed with an oblique electric field. Moreover, since the auxiliary electrodes 4 are made of the same film as the semiconductor layer 12 of the thin film transistor 1, a high light transmittance can be provided. For example, an auxiliary electrode 4 which is made of continuous grain silicon (CGS) can realize a light transmittance of about 80% with a thickness of about 50 nm. Furthermore, since the auxiliary electrodes 4 are made of the same film as the semiconductor layer 12 of the thin film transistor 1, hardly any new steps for providing the auxiliary electrodes 4 are needed. Therefore, it is possible to suppress decrease in light transmittance without much increase in the number of production steps.

The present embodiment illustrates as a switching element the thin film transistor 1 including the semiconductor layer 12 which is made of continuous grain silicon; however, the switching element is not limited thereto. The semiconductor layer 12 may be made of crystalline silicon such as continuous grain silicon or polycrystalline silicon, or made of amorphous silicon.

FIG. 7 and FIG. 8 show a liquid crystal display device 100′ having thin film transistors 1′ including a semiconductor layer 12 which is made of amorphous silicon. The liquid crystal display device 100 shown in FIG. 2 and FIG. 3 has the top-gate type thin film transistors 1 including the semiconductor layer 12 made of continuous grain silicon, whereas the liquid crystal display device 100′ shown in FIG. 7 and FIG. 8 has the bottom-gate type thin film transistors 1′ including the semiconductor layer 12 made of amorphous silicon.

The liquid crystal display device 100′ also includes auxiliary electrodes 4 made of the same film as the semiconductor layer 12 of the thin film transistor 1′ (i.e., made of amorphous silicon). Therefore, effects similar to those of the liquid crystal display device 100 are obtained. The thickness of the auxiliary electrode 4 made of amorphous silicon is about 35 nm, for example.

Note that, in each of the liquid crystal display devices 100 and 100′, the thickness of the auxiliary electrodes 4 is not limited to the exemplified value. However, in order to sufficiently suppress decrease in the light transmittance of a pixel, the auxiliary electrodes 4 are preferably formed with a thickness such that it has a light transmittance of 60% or more, and more preferably 80% or more. An auxiliary electrode 4 made of crystalline silicon can realize a light transmittance of 80% or more with a thickness of 60 nm or less, and a light transmittance of 60% or more with a thickness of 114 nm or less. Note that the semiconductor layer 12 of the switching element and the auxiliary electrodes 4 do not need to have the same thickness, and they may have respectively different thicknesses. However, from the standpoint of suppressing increase in the number of steps, it is preferable that they have almost the same thickness.

FIG. 1 to FIG. 3, FIG. 7, and FIG. 8 illustrate constructions where the electrically-conductive film of a pixel electrode 2 and an auxiliary electrode 4 do not overlap each other. However, as shown in FIG. 9, the auxiliary electrode 4 may include portions 4 c which overlap the electrically-conductive film of the pixel electrode 2, and the region where each portion 4 c overlaps the pixel electrode 2 may be used as a portion of a storage capacitor.

Embodiment 2

With reference to FIG. 10 to FIG. 12, the structure of a liquid crystal display device 200 according to the present embodiment will be described. FIG. 10 is an upper plan view schematically showing a region corresponding to one pixel of the liquid crystal display device 200. FIG. 11 and FIG. 12 are cross-sectional views taken along line 11A-11A′ and line 12A-12A′ in FIG. 10, respectively.

As shown in FIG. 10 to FIG. 12, the liquid crystal display device 200 includes auxiliary electrodes 4 which are made of the same film as the semiconductor layer 12 of the thin film transistors 1, and therefore is able to stably perform orientation control with an oblique electric field, and suppress decrease in light transmittance while suppressing increase in the number of steps.

However, the liquid crystal display device 200 of the present embodiment differs from the liquid crystal display device 100 of Embodiment 1 in terms of the manner of electrical connection between an auxiliary electrode 4 and a storage capacitor line 16. In the liquid crystal display device 100, as is also shown in FIG. 3, an auxiliary electrode 4 is connected to a storage capacitor line 16 through a contact hole which is provided in the gate insulating film 13, thus being electrically connected to the storage capacitor line 16 within each pixel.

On the other hand, in the liquid crystal display device 200, as can also be seen from FIG. 12, the auxiliary electrode 4 is not connected to the storage capacitor line 16 within the pixel. The auxiliary electrode 4 in the present embodiment is electrically connected to the storage capacitor line 16 outside a displaying region which is defined by a plurality of pixels (also referred to as the peripheral region).

Specifically, as shown in FIG. 13, each auxiliary electrode 4 includes a portion 4 d which is connected to the auxiliary electrode 4 of an adjoining pixel, and a plurality of auxiliary electrodes 4 which are mutually connected via the portions 4 d are electrically connected to the storage capacitor line 16 via a connection electrode 5 which is provided outside the displaying region (peripheral region).

The connection electrode 5 in the present embodiment is made of the same film as the signal line 20. The connection electrode 5 is formed as shown in FIGS. 14( a) to (c). FIGS. 14( a) to (c) are step-by-step cross-sectional views showing steps of forming the connection electrode 5, corresponding to a cross section along 14A-14A′ in FIG. 13.

FIG. 14( a) shows, in the steps of producing the active matrix substrate 60, a state where the basecoat film 11, the auxiliary electrodes 4, the gate insulating film 13, the storage capacitor lines 16, and the first interlayer insulating film 17 have been stacked on the transparent substrate 10.

After the first interlayer insulating film 17 is deposited, the gate insulating film 13 and the first interlayer insulating film 17 above the portions of the semiconductor layer 12 to become source regions and gate regions are removed, whereby contact holes are formed. At this time, as shown in FIG. 14( b), contact holes are also formed outside the displaying region. Specifically, outside the displaying region, two contact holes are formed by removing the gate insulating film 13 and the first interlayer insulating film 17 above an auxiliary electrode 4 and the first interlayer insulating film 17 above a storage capacitor line 16.

Thereafter, by depositing an electrically-conductive film on the first interlayer insulating film 17 and then patterning the electrically-conductive film, the source electrodes 18, the drain electrodes 19, and the signal lines 20 are formed. At this time, as shown in FIG. 14( c), the connection electrode 5 is also formed.

As shown in FIG. 3, in the case where the auxiliary electrode 4 and the storage capacitor line 16 are connected within the pixel through a contact hole which is formed in the gate insulating film 13, a step of forming the contact hole in the gate insulating film 13 is required. On the other hand, in the case where the connection electrode 5 is formed in the above-described manner, it is possible to electrically connect the auxiliary electrodes 4 and the storage capacitor lines 16 without adding any steps. Moreover, since the connection electrode 5 is provided outside the displaying region, the connection electrode 5 will not deteriorate the light transmittance of the pixels.

Also in the present embodiment, the thin film transistor 1 including the semiconductor layer 12 which is made of continuous grain silicon is illustrated a switching element; however, the switching element is not limited thereto. The semiconductor layer 12 may be made of crystalline silicon such as continuous grain silicon or polycrystalline silicon, or made of amorphous silicon.

FIG. 15 and FIG. 16 show a liquid crystal display device 200′ having a thin film transistor 1′ including a semiconductor layer 12 which is made of amorphous silicon. The liquid crystal display device 200 shown in FIG. 11 and FIG. 12 has the top-gate type thin film transistors 1 including the semiconductor layer 12 made of continuous grain silicon, whereas the liquid crystal display device 200′ shown in FIG. 15 and FIG. 16 has the bottom-gate type thin film transistors 1′ including the semiconductor layer 12 made of amorphous silicon.

The liquid crystal display device 200′ also includes auxiliary electrodes 4 which are made of the same film as the semiconductor layer 12 of the thin film transistors 1′ (i.e., made of amorphous silicon). Therefore, it is possible to stably perform orientation control with an oblique electric field, and also suppress decrease in light transmittance.

In the liquid crystal display device 200′, too, as can also be seen from FIG. 16, the auxiliary electrode 4 is not connected to a storage capacitor line 16 within the pixel, but is electrically connected to the storage capacitor line 16 outside the displaying region (peripheral region). In the peripheral region, the auxiliary electrode 4 is connected to a storage capacitor line 16 through contact holes which are provided in the gate insulating film 13, for example. In this case, a step of forming contact holes in the gate insulating film 13 is required. However, under specifications where a portion of the gate insulating film 13 is meant to be removed because of a certain requirement anyway, the auxiliary electrode 4 and the storage capacitor line 16 can be electrically connected without adding any steps, by utilizing the step of patterning the gate insulating film 13 as an opportunity to form the contact holes.

Note that, in the liquid crystal display device 100 of Embodiment 1, as shown in FIG. 17( a), the auxiliary electrode 4 and the storage capacitor line 16 are directly connected through a contact hole which is provided in the gate insulating film 13 within the pixel. FIG. 17( a) is a cross-sectional view showing the neighborhood of the storage capacitor line 16 in FIG. 3, corresponding to a cross section along line 17A-17A′ in FIG. 1. Instead of employing this construction, as shown in FIG. 17( b), a connection electrode 5 which is made of the same film as the signal line 20 may be provided within the pixel, and the auxiliary electrode 4 and the storage capacitor line 16 may be electrically connected with the connection electrode 5. By adopting such a construction, without adding any steps, the auxiliary electrode 4 and the storage capacitor line 16 can be electrically connected.

However, in the case where a connection electrode 5 is provided within the pixel, the light transmittance of the pixel may be lowered, depending on the relative positioning of the auxiliary electrode 4 and the storage capacitor line 16. For example, as shown in FIGS. 18( a) and (b), if the connection electrode 5 is provided in the case where the auxiliary electrode 4 and the storage capacitor line 16 do not overlap, there will be a region that is shaded by the connection electrode 5, and thus the light transmittance of the pixel will be deteriorated.

On the other hand, in the case where the auxiliary electrode 4 and the storage capacitor line 16 partially overlap, as shown in FIGS. 19( a) and (b), the width of the shaded region can be reduced, thus making it possible to suppress decrease in light transmittance. Moreover, in the case where the auxiliary electrode 4 and the storage capacitor line 16 partially overlap, as shown in FIGS. 20( a) and (b), a contact hole may be formed in the storage capacitor line 16, and the connection electrode 5 may be disposed so that its entirety overlaps the storage capacitor line 16; thus, there will be no shaded region, and lowering of the light transmittance can be prevented.

Embodiment 3

In Embodiments 1 and 2, the present invention has been described by taking a transmission type liquid crystal display device which presents display in the transmission mode as an example. However, the present invention is also suitably used for a transmission/reflection combination type liquid crystal display device which is capable of presenting display in both of the transmission mode and the reflection mode.

FIG. 21 and FIG. 22 show a liquid crystal display device 300 according to the present embodiment. FIG. 21 is an upper plan view schematically showing a region corresponding to one pixel of the liquid crystal display device 300. FIG. 22 is a cross-sectional view along line 22A-22A′ in FIG. 21.

Each pixel of the liquid crystal display device 300 includes a transmission region T which presents display in the transmission mode and a reflection region R which presents display in the reflection mode. A pixel electrode 2 of the liquid crystal display device 300 includes a transparent electrode 2T which is made of an electrically conductive material having a high light transmittance (e.g. ITO) and a reflection electrode 2R which is made of an electrically conductive material having a high light reflectance (e.g. aluminum). The transparent electrode 2T is formed across both of the two subpixels, whereas the reflection electrode 2R is selectively formed in only one of the subpixels, so that the region where the reflection electrode 2R is formed functions as the reflection region R.

Moreover, a transparent dielectric layer 35 is provided in the region of the counter substrate 70 corresponding to the reflection region R, so that the thickness of the liquid crystal layer 50 in the reflection region R is smaller than the thickness of the liquid crystal layer 50 in the transmission region T. The light which is utilized in the reflection mode travels through the liquid crystal layer 50 twice, whereas the light which is utilized in the transmission mode travels through the liquid crystal layer 50 only once. However, as mentioned above, the liquid crystal layer 50 in the reflection region R is made thinner than the liquid crystal layer 50 in the transmission region T, so that the optical path difference between the reflection region R and the transmission region T can be reduced. As a result, display can be suitably presented in both of the reflection region R and the transmission region T.

The liquid crystal display device 300 also includes auxiliary electrodes 4 which are made of the same film as the semiconductor layer 12 of the thin film transistor 1. Therefore, it is possible to stably perform orientation control with an oblique electric field and also suppress decrease in light transmittance without much increase in the number of production steps.

Note that Embodiments 1, 2, and 3 described above illustrate constructions where orientation restriction structures (recessed portions 2 a of the pixel electrode 2) are provided only on the active matrix substrate 60. However, as necessary, orientation restriction structures may be provided also on the counter substrate 70.

FIG. 23 and FIG. 24 show a liquid crystal display device 400 which has orientation restriction structures also on the counter substrate 70. As shown in FIG. 23 and FIG. 24, the liquid crystal display device 400 differs from the liquid crystal display device 100 of Embodiment 1 in that protrusions 6 are provided on the counter substrate 70.

Each protrusion 6 projecting toward the liquid crystal layer 50 has a slanted side face, and an orientation restriction force is exhibited due to an anchoring effect of the vertical alignment film 33 on this side face. The orientation restriction force due to the protrusion 6 acts to orient the liquid crystal molecules 51 in the same directions as the orientation restriction forces due to the recessed portions 2 a of the pixel electrode 2, so that the axisymmetric orientation of the liquid crystal molecules 51 in the subpixel is further stabilized. Moreover, since the axisymmetric orientation is created around the protrusion 6 which is provided in the substantial center of a subpixel (i.e., the protrusion 6 is provided in a region corresponding to the substantial center of a liquid crystal domain), the center of the axisymmetric orientation is fixed near the protrusion 6.

Thus, the axisymmetric orientation can be stabilized by: restricting the orientation directions, mainly, the liquid crystal molecules 51 around the subpixel with the orientation restriction structures provided on the one substrate (the recessed portions 2 a or apertures of the pixel electrode 2), and restricting the orientations of the liquid crystal molecules 51 at the central portion of the subpixel with the orientation restriction structure (protrusion 6) provided on the other substrate. This makes it possible to shorten the response time in gray-scale displaying, and the time in which a disturbance in orientation resulting from pressing the panel surface is eliminated.

Note that the orientation restriction structures to be provided on the counter substrate 70 are not limited to the protrusion 6 as illustrated. For example, apertures located at the subpixel centers may be provided on the counter electrode 3.

INDUSTRIAL APPLICABILITY

According to the present invention, in a vertical alignment mode liquid crystal display device, it is possible to stably perform orientation control with an oblique electric field, and also suppress decrease in light transmittance without much increase in the number of production steps. The present invention is suitably used for a transmission type or transmission/reflection combination type liquid crystal display device which is active-matrix driven.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US4345249Dec 12, 1980Aug 17, 1982Citizen Watch Company LimitedLiquid crystal display panel
US4368523Dec 16, 1980Jan 11, 1983Tokyo Shibaura Denki Kabushiki KaishaLiquid crystal display device having redundant pairs of address buses
US4889412Feb 17, 1987Dec 26, 1989Commissariat A L'energie AtomiqueLiquid crystal cell using the electrically controlled birefringence effect and a uniaxial medium of negative optical anisotropy usable therein
US4955698Mar 3, 1989Sep 11, 1990Robert Bosch GmbhOpto-electronic indicating matrix, and indicating device provided therewith
US5132819Jan 17, 1991Jul 21, 1992Kabushiki Kaisha ToshibaLiquid-crystal display device of active matrix type having connecting means for repairing defective pixels
US5164851Jan 31, 1991Nov 17, 1992Sharp Kabushiki KaishaActive matrix display device having spare switching elements connectable to divisional subpixel electrodes
US5179456Sep 27, 1991Jan 12, 1993Stanley Electric Co., Ltd.Optical birefringence compensator
US5182664Dec 18, 1990Jan 26, 1993Stanley Electric Co., Ltd.Liquid crystal display having electrically controlled birefringence
US5245450Jul 19, 1991Sep 14, 1993Hosiden CorporationLiquid crystal display device with control capacitors for gray-scale
US5260818May 11, 1992Nov 9, 1993Industrial Technology Research InstituteDisplay panel provided with repair capability of defective elements
US5289174Jul 14, 1992Feb 22, 1994Kabushiki Kaisha ToshibaLiquid crystal display device
US5309264Apr 30, 1992May 3, 1994International Business Machines CorporationLiquid crystal displays having multi-domain cells
US5331447Jul 8, 1992Jul 19, 1994Hitachi, Ltd.TFT active matrix liquid crystal display devices with plural TFTs in parallel per pixel
US5363294Mar 27, 1992Nov 8, 1994Nissha Printing Co., Ltd.Surface light source device
US5408345Jun 24, 1994Apr 18, 1995Sharp Kabushiki KaishaReflection type liquid crystal display device wherein the reflector has bumps
US5434687Mar 11, 1994Jul 18, 1995Kabushiki Kaisha ToshibaLiquid crystal display device having polarization areas or orientation areas in radial or concentric ring pattern
US5477358Jun 21, 1993Dec 19, 1995Case Western Reserve UniversityChiral nematic liquid crystal display with homeotropic alignment and negative dielectric anisotropy
US5508834Mar 3, 1994Apr 16, 1996Sony CorporationLiquid crystal display device having polarizers and microlens arrays attached to transparent cover members
US5512336Nov 18, 1994Apr 30, 1996Sharp Kabushiki KaishaOrientation layer composed of polymer alloy; phase separation structure; high contrast; no display unevenness
US5558927Sep 17, 1993Sep 24, 1996Seiko Epson CorporationColor filter for liquid crystal displays and film-forming apparatus
US5594570May 30, 1995Jan 14, 1997Sharp Kabushiki KaishaLiquid crystal display device and method for producing the same
US5602662Feb 16, 1995Feb 11, 1997Case Western Reserve UniversityCholesteric liquid crystal devices
US5608556Jun 21, 1994Mar 4, 1997Sanyo Electric Co., Ltd.Liquid crystal display having orientation control electrodes for controlling liquid crystal orientation
US5636043Aug 23, 1994Jun 3, 1997Matsushita Electric Industrial Co., Ltd.Liquid crystal display device having partitioned unit liquid crystal cells
US5646702Oct 31, 1994Jul 8, 1997Honeywell Inc.Field emitter liquid crystal display
US5666179Sep 12, 1996Sep 9, 1997Sanyo Electric Co., Ltd.Liquid crystal display device having opening formed in electrode
US5668651Feb 27, 1995Sep 16, 1997Sharp Kabushiki KaishaPolymer-wall LCD having liquid crystal molecules having a plane-symmetrical bend orientation
US5673092Jun 7, 1995Sep 30, 1997Sharp Kabushiki KaishaLiquid crystal device and method for fabricating the same
US5699137Aug 15, 1996Dec 16, 1997Sharp Kabushiki KaishaLiquid crystal display device having compensator with particular retardation in the inclined direction
US5726728Sep 27, 1994Mar 10, 1998Sharp Kabushiki KaishaLiquid crystal display device and a production method utilizing surface free energies for the same
US5748276Dec 9, 1996May 5, 1998Matsushita Electric Industrial Co., Ltd.Liquid crystal display unit with a plurality of subpixels
US5753093Apr 9, 1997May 19, 1998Australian Membrane And Biotechnology Research InstituteSensor membranes
US5995176Mar 21, 1997Nov 30, 1999Nec CorporationLiquid crystal display apparatus having pixels of different orientation of liquid crystal capable of shielding leakage of light through the discontinuity of orientation
US6031591Feb 12, 1999Feb 29, 2000Nippon Sheet Glass Co., Ltd.Liquid-crystal display device
US6061117Jul 14, 1997May 9, 2000Sharp Kabushiki KaishaLiquid crystal device having a polymer wall on another wall and surrounding a liquid crystal region and method for fabricating the same
US6069740Jun 16, 1999May 30, 2000Nippon Sheet Glass Co., Ltd.Planar microlens array and method of manufacturing same
US6097464Jan 14, 2000Aug 1, 2000Industrial Technology Research InstituteMulti-domain homeotropic aligned liquid crystal display having cruciform bumps formed around pixel electrodes
US6129439Mar 26, 1997Oct 10, 2000Alliedsignal Inc.Illumination system employing an array of multi-faceted microprisms
US6141077May 26, 1999Oct 31, 2000Sharp Kabushiki KaishaLiquid crystal display including pixel electrode(s) designed to improve viewing characteristics
US6169593Dec 11, 1998Jan 2, 2001Sharp Kabushiki KaishaReflection-type liquid crystal display device, method for producing the same, and method for producing circuit board
US6175398Jul 2, 1996Jan 16, 2001Sharp Kabushiki KaishaAxial symmetric polarizing plate, method for fabricating the same, and liquid crystal display device
US6195140Jul 27, 1998Feb 27, 2001Sharp Kabushiki KaishaLiquid crystal display in which at least one pixel includes both a transmissive region and a reflective region
US6201592May 25, 1999Mar 13, 2001Sharp Kabushiki KaishaLiquid crystal display device and method for producing the same
US6222599Mar 31, 1999Apr 24, 2001Fujitsu LimitedLiquid crystal display apparatus including a color filter having slits
US6256082Oct 5, 1998Jul 3, 2001Nec CorporationLiquid crystal display with a liquid crystal orientation controlling electrode and processes for manufacturing and driving thereof
US6266122Jun 10, 1999Jul 24, 2001Sharp Kabushiki KaishaLiquid crystal display device and method for manufacturing the same
US6287649Jun 17, 1998Sep 11, 2001Seiko Epson CorporationLiquid crystal display device and method of manufacturing it
US6330047Mar 10, 2000Dec 11, 2001Sharp Kabushiki KaishaLiquid crystal display device and method for fabricating the same
US6335780Jul 20, 1999Jan 1, 2002Sharp Kabushiki KaishaLCD with protrusion structures for axially symmetrically aligning liquid crystal in regions smaller than 70 μm×70 μm
US6339462Jun 29, 1999Jan 15, 2002Sharp Kabushiki KaishaLCD having polymer wall and column-like projection defining cell gap
US6340998Mar 29, 1999Jan 22, 2002Samsung Display Devices Co., LtdThin film transistor liquid crystal display including at least three transistors associated with an unit pixel
US6341002Oct 14, 1999Jan 22, 2002Sharp Kabushiki KaishaLiquid crystal display device
US6342938May 19, 1999Jan 29, 2002Samsung Electronics Co., Ltd.Liquid crystal display having electrodes with apertures wherein the apertures have different shapes
US6384887Oct 18, 1999May 7, 2002Sony CorporationPair of substrates having transparent electrodes, carbon black fine particles and an alignment film comprising ytterbium diphpthalocyanine between the substrates
US6384889Jul 20, 1999May 7, 2002Sharp Kabushiki KaishaLiquid crystal display with sub pixel regions defined by sub electrode regions
US6504592Jun 13, 2000Jan 7, 2003Nec CorporationLiquid crystal display and method of manufacturing the same and method of driving the same
US6512564Feb 25, 1998Jan 28, 2003Fujitsu LimitedAlignment treatment of liquid crystal display device
US6542212Mar 2, 2001Apr 1, 2003Fujitsu LimitedLiquid crystal display apparatus with comb-shaped electrodes
US6567144May 20, 1999May 20, 2003Samsung Electronics Co., Ltd.Liquid crystal display having a wide viewing angle
US6573964Dec 23, 1999Jun 3, 2003Fujitsu Display Technologies CorporationMultidomain vertically aligned liquid crystal display device
US6573965Jun 18, 2000Jun 3, 2003Industrial Technology Research InstituteMulti-domain wide viewing angle liquid crystal display having slits on electrodes and bumps above the slits
US6577366Oct 13, 1999Jun 10, 2003Samsung Electronics Co., Ltd.Patterned vertically aligned liquid crystal display
US6593982Dec 4, 2000Jul 15, 2003Samsung Electronics Co., Ltd.Liquid crystal display with color filter having depressed portion for wide viewing angle
US6600539Jun 13, 2001Jul 29, 2003Samsung Electronics Co., Ltd.Vertically-aligned liquid crystal display with a small domain
US6614497May 29, 2001Sep 2, 2003Chi Mei Optoelectronics Corp.Liquid crystal display device having particular pixel electrodes
US6630975Feb 25, 2000Oct 7, 2003Sharp Kabushiki KaishaLiquid crystal display device, and method for producing the same
US6633351Jan 19, 2001Oct 14, 2003Hitachi, Ltd.Optical functionality sheet, and planar light source and image display apparatus using the same sheet
US6657695Apr 27, 2000Dec 2, 2003Samsung Electronics Co., Ltd.Liquid crystal display wherein pixel electrode having openings and protrusions in the same substrate
US6661488Sep 18, 2000Dec 9, 2003Fujitsu LimitedVertically-alligned (VA) liquid crystal display device
US6710825Aug 2, 2001Mar 23, 2004Sharp Kabushiki KaishaLCD including pixel electrode with multiple sub-electrode portions
US6717642Oct 9, 2002Apr 6, 2004Nitto Denko CorporationWide viewing angle polarizer and liquid-crystal display device
US6784961May 30, 2001Aug 31, 2004Sony CorporationApparatus and method for displaying image
US6788375Apr 11, 2002Sep 7, 2004Sharp Kabushiki KaishaLiquid crystal display device
US6812986Sep 23, 2002Nov 2, 2004Nec CorporationLiquid crystal display and method of manufacturing the same and method of driving the same
US6822723Jun 25, 2001Nov 23, 2004Samsung Electronics Co., Ltd.Liquid crystal display with a wide viewing angle
US6829026Oct 7, 2002Dec 7, 2004Nitto Denko CorporationLaminated phase retarder having a cholesteric liquid crystal layer, polarizing member and liquid crystal display device
US6839108May 13, 1999Jan 4, 2005Semiconductor Energy Laboratory Co., Ltd.Liquid crystal display device and method of manufacturing the same
US6862062Feb 11, 2004Mar 1, 2005Sharp Kabushiki KaishaLiquid crystal display device
US6894840May 12, 2003May 17, 2005Sony CorporationProduction method of microlens array, liquid crystal display device and production method thereof, and projector
US6924856Jun 14, 2002Aug 2, 2005Nec Lcd Technologies, Ltd.Liquid-crystal display device and method of fabricating the same
US6924876Feb 23, 2001Aug 2, 2005Sharp Kabushiki KaishaLiquid crystal display device
US6950160Dec 31, 2003Sep 27, 2005Sharp Kabushiki KaishaLiquid crystal display device with domains formed over solid and open portions of an electrode
US6965422Dec 2, 2002Nov 15, 2005Sharp Kabushiki KaishaLiquid crystal display device
US6967702Aug 1, 2003Nov 22, 2005Nec Lcd Technologies, Ltd.Liquid crystal display device
US6989874Oct 1, 2002Jan 24, 2006Lg.Philips Lcd Co., Ltd.Substrate structure of liquid crystal display and fabrication method thereof
US6995826May 14, 2004Feb 7, 2006Sharp Kabushiki KaishaLiquid crystal display device
US7084943Apr 13, 2005Aug 1, 2006Sharp Kabushiki KaishaLiquid crystal display device
US7139055Jul 27, 2004Nov 21, 2006Sharp Kabushiki KaishaLiquid crystal display device having liquid crystal domains with radially-inclined orientation
US7145624May 6, 2004Dec 5, 2006Sharp Kabushiki KaishaLiquid crystal display device having multiple domains with radially inclined LC molecules
US7202923Feb 27, 2004Apr 10, 2007Sharp Kabushiki KaishaLiquid crystal display with polarizer with inclined edge portion
US7215395Aug 8, 2001May 8, 2007Sharp Kabushiki KaishaLiquid crystal display device
US7230664Oct 25, 2001Jun 12, 2007Sharp Kabushiki KaishaLiquid crystal display device
US7253872Sep 29, 2004Aug 7, 2007Sharp Kabushiki KaishaLiquid crystal display apparatus comprising wall portions formed in a plurality of openings or cut-out portions of an electrode
US7277146May 11, 2004Oct 2, 2007Seiko Epson CorporationVertical alignment mode LCD with larger dielectric protrusions in transmissive region than in reflection region
US7292300Jun 23, 2003Nov 6, 2007Sharp Kabushiki KaishaLiquid crystal display with radially-inclined liquid crystal in unit solid portions arranged in a single direction
US7375781Dec 22, 2004May 20, 2008Sharp Kabushiki KaishaLiquid crystal display device
US7379137Feb 2, 2005May 27, 2008Sharp Kabushiki KaishaLiquid crystal display device
US7391489Mar 8, 2005Jun 24, 2008Sharp Kabushiki KaishiaLiquid crystal display device
US7499136Apr 26, 2005Mar 3, 2009Sharp Kabushiki KaishaLiquid crystal display device
US20060114405 *Nov 29, 2005Jun 1, 2006Casio Computer Co., Ltd.Vertical alignment active matrix liquid crystal display device
US20060139541 *Dec 19, 2005Jun 29, 2006Casio Computer Co., Ltd.Vertical alignment liquid crystal display device
Non-Patent Citations
Reference
1A. Funamoto et al., "Prism-Sheetless High Bright Backlight System for Mobile Phone", IDW'04, pp. 687-690.
2English translation of International Preliminary Report on Patentability mailed in PCT Application No. PCT/JP2007/070907.
3English translation of the International Preliminary Report on Patentability mailed Feb. 14, 2008 in PCT Application No. PCT/JP2006/315142.
4English translation of the International Preliminary Report on Patentability mailed Jan. 7, 2010 in corresponding PCT Application No. PCT/ JP2008/001350.
5English translation of the International Preliminary Report on Patentability mailed Oct. 29, 2009 in corresponding PCT Application No. PCT/JP2007/074635.
6English translation of the International Preliminary Report on Patentability mailed Oct. 30, 2008 in PCT Application No. PCT/JP2007/053037.
7EP Supplementary Search Report mailed Dec. 17, 2009 in EP application 07791179.0.
8EP Supplementary Search Report mailed Dec. 29, 2009 in EP application 07806137.1.
9Final Office Action mailed Jul. 20, 2011 in U.S. Appl. No. 12/440,791.
10Final U.S. Office Action mailed Apr. 30, 2009 in U.S. Appl. No. 12/081,752.
11International Preliminary Report on Patentability mailed Apr. 9, 2009 in PCT Application No. PCT/JP2007/064447.
12International Preliminary Report on Patentability mailed Apr. 9, 2009 in PCT Application No. PCT/JP2007/066658.
13International Preliminary Report on Patentability mailed Jul. 2, 2009 in PCT Application No. PCT/JP2007/073231.
14International Preliminary Report on Patentability mailed Mar. 26, 2009 in corresponding PCT Application No. PCT/JP2007/064448.
15International Search Report for PCT/JP2006/315142 mailed Aug. 22, 2006.
16International Search Report for PCT/JP2007/053037, mailed Mar. 27, 2007.
17International Search Report for PCT/JP2007/064448 mailed Aug. 21, 2007.
18International Search Report for PCT/JP2007/066658, mailed Dec. 4, 2007.
19International Search Report for PCT/JP2007/070907, mailed Nov. 20, 2007.
20International Search Report for PCT/JP2007/073231, mailed Feb. 12, 2008.
21International Search Report for PCT/JP2007/074635, mailed Jan. 29, 2008.
22International Search Report mailed Jul. 1, 2008 in PCT application PCT/JP2008/001350.
23Jignesh Gandhi et al., "Performance Enhancement of reflective CMOS Twistes Nematic Disp Projection Applications Using Compensating Films", pp. 1-6, reprinted from http://www/hanoah.com/publications/sid99 paper Jignesh final pdf. (1999).
24Jisaki et al, "Development of transflective LCD for high contrast and wide viewing angle by using homeotropic alignment", Asia Display/IDW '01, pp. 133-136.
25K. Kalantar, "Viewing Angle Control using Optical Microstructures on Light-Guide Plate for Illumination System of Mobile Transmissive LCD Module", IDW'02, pp. 549-552.
26KR Notice of Reasons for Rejection and English translation thereof mailed Apr. 25, 2006 in corresponding Korean application No. 10-2004-0110955.
27Kubo et al., "Development of High-Performance ASV-LCDs Using Continuous Pinwheel Alignment (CPA) Mode", pp. 1-5, Jun. 7, 2001.
28Notice of Allowance mailed Apr. 27, 2011 in U.S. Appl. No. 11/997,563.
29Notice of Allowance mailed Jul. 11, 2011 in U.S. Appl. No. 12/443/015.
30Notice of Allowance mailed Mar. 7, 2011 in related U.S. Appl. No. 12/293,895.
31Suqita et al, "Brightness Enhancement in Transflective LCD by Concentration of Uniaxially Collimated Light with a Micro-Lenticular Lens", , IDW 2007, pp. 1515-1518.
32Thomson-CSFILR-Jan. 2000, "Optical compensation for displays".
33U.S. Appl. No. 11/997,563, filed Feb. 1, 2008, naming Masumi Kubo, as inventor.
34U.S. Appl. No. 12/293,895, filed Sep. 22, 2008, naming Masaaki Saitoh et al., as inventors.
35U.S. Office Action mailed Feb. 17, 2011 in related U.S. Appl. No. 12/442,218.
36U.S. Office Action mailed Feb. 2, 2011 in U.S. Appl. No. 12/440,791.
37U.S. Office Action mailed Jul. 29, 2011 in related U.S. Appl. No. 12/293,895.
38U.S. Office Action mailed Jun. 23, 2010 in U.S. Appl. No. 11/997,563.
39U.S. Office Action mailed Nov. 14, 2008 in U.S. Appl. No. 12/081,752.
Referenced by
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US20100007815 *Aug 28, 2007Jan 14, 2010Seishi KosegawaLiquid crystal display panel with microlens array, its manufacturing method, and liquid crystal display device
US20120140153 *Jun 8, 2010Jun 7, 2012Sharp Kabushiki KaishaLiquid crystal display device
US20120236242 *Dec 30, 2011Sep 20, 2012Ong Hiap LLiquid Crystal Displays Having Pixels with Embedded Fringe Field Amplifiers
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Classifications
U.S. Classification349/130, 349/143, 349/38, 349/129, 349/39, 349/134
International ClassificationG02F1/141, G02F1/1343, G02F1/1337
Cooperative ClassificationG02F1/134309, G02F1/133707, G02F1/1393
European ClassificationG02F1/139E, G02F1/1337B
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Owner name: SHARP KABUSHIKI KAISHA, JAPAN